Because nobody agrees what web3 even means, it's a totally useless term, not that dissimilar to AGI or consciousness, which nobody can properly define. People who hate crypto define web3 in terms of all the negative stuff, while people who have a vested interested in pumping token prices (like VCs) will define web3 in terms of all the potentially positive stuff.
I believe that the that fundamentals of crypto are incredibly useful and will eventually be adopted, and have been in meany places, but all the web3/NFT/etc stuff (whatever that means) is just useless hype and ponzi schemes.
Crypto has a much more negative image because it's full of scams, but that doesn't mean anything. It's just significantly easier to create scams with crypto because money is at the very base layer, than it is to create scams with AI. But that doesn't imply anything about the usefulness of these technologies.